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  1. #include<vector>
  2. #include<iostream> 
  3. class X
  4.     {
  5.         std::vector<double> data;
  6.     public:
  7.     	// Constructor1
  8.         X():
  9.             data(100000) // lots of data
  10.         {}
  11.  
  12.     	// Constructor2
  13.         X(X const& other): // copy constructor
  14.             data(other.data)   // duplicate all that data
  15.         {}
  16.  
  17.     	// Constructor3
  18.         X(X&& other):  // move constructor
  19.             data(std::move(other.data)) // move the data: no copies
  20.         {std::cout<<"\nMove constructor";}
  21.  
  22.         X& operator=(X const& other) // copy-assignment
  23.         {
  24.             std::cout<<"\nCopy assignment";
  25.             data=other.data; // copy all the data
  26.             return *this;
  27.         }
  28.  
  29.         X& operator=(X && other) // move-assignment
  30.         {
  31.             std::cout<<"\nMove assignment";
  32.             data=std::move(other.data); // move the data: no copies
  33.             return *this;
  34.         }
  35.  
  36.     };
  37.  
  38.     X make_x() // build an X with some data
  39.     {
  40.     	X myNewObject; // Constructor1 gets called here
  41.     	// fill data..
  42.     	return myNewObject; // Constructor3 gets called here
  43.     }
  44.  
  45.  
  46.     int main()
  47.     {
  48.     	X x1;
  49.         //X x2(x1); // copy
  50.         //X x3(std::move(x1)); // move: x1 no longer has any data
  51.  
  52.         x1=make_x(); // return value is an rvalue, so move rather than copy
  53.     }
Success #stdin #stdout 0s 2852KB
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stdin
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Standard input is empty
stdout
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Move assignment
https://ideone.com/g8Br60
language:
C++14 (gcc 8.3)
created:
12 years ago
visibility:
public

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